若尔盖草原NDVI的季节特点和变化规律

文章使用NOAA17/AVHRR数据,采用归一化差值植被指数(NDVI)模型,对2006年3月～2007年2月若尔盖及周边地区进行计算和分析得出,NDVI在7月最大,12月最小;结合降水量和气温的年变化,分析了NDVI的季节特点和变化规律的气候基础.     

河流水质评价中模糊数学评价法的应用与比较

选择2005年6个典型日（1月12日、3月10目、5月10日、7月13日、9月8日和11月10日）的水质,运用两种模糊数学评价法对浙江西苕溪流域港口断面的水质进行评价并作比较。第一种数学评价法采用较为简单的单因素模糊综合评价法,另一种采用多级模糊数学评价法。评价结果表明,1月12日、3月10日和11月10日的水质达到国家Ⅰ类水质标准;而5月10目的水质相对最差。比较两种评价方法,单因素模糊综合评价法对单个因素的影响敏感,特别是超标值对最后的相对隶属度贡献大;而多级模糊评价法综合各个因素来评价现状水质,因而反映出水质的综合情况。结合港口断面的特点分析水质变差的原因,结论是：流域农业劳作带来的面源污染物质进入港口断面使得该断面在农作高峰期水质较差;同时,断面的水资源短缺问题较为严重,导致水环境容量较小,污染物较难稀释扩散。     

秦皇岛雷暴天气的时空尺度分布与雷电灾害分析

利用2003-2012年3～10月秦皇岛地区5个气象站雷暴监测和雷电灾害资料,采用数理统计、天气综合分析方法,得出秦皇岛地区雷暴天气的时空尺度分布特征为：全区年雷暴发生频次总体上呈递减趋势,其中,2005年35次,2008年33次,2012年20次;6月份为全年雷暴发生的峰值时段,7月、8月次之,且与秦皇岛本地主汛期相吻合;在海岸带地区由于受海洋条件影响,个别年份雷暴最早出现在2月份,最晚出现在11月中旬;雷暴天气的日时段主要出现在下午至傍晚,占70%,夜间占20%,其他时段为10%;北部山区的雷电频次大于沿海地区,对应电力、化工等行业雷电灾害呈下降趋势,但是通讯、计算机、家电等弱电系统雷击事件呈递增趋势。     

外来游客流入的就业溢出效应分析CSSCI

外来游客流入多少才能刺激地区产业部门的就业增长?由于目前旅游统计体系缺少外来游客量统计数据,将星级饭店出租床位数作为外来游客流入量的替代变量,建立外来游客流入就业溢出效应测度模型,利用2006—2012年中国31个省区的数据,采用包括GMM动态面板模型在内多种估计方法,测度外来游客流入就业溢出效应。结果表明,每个地区每天增加1个单位(1000个床位)出租床位数,在各非餐饮住宿产业平均增加0.043%—0.102%的就业机会。     

郑州市耕地资源安全的时空特征分析

耕地资源安全是保障我国国民经济发展的重要条件之一,又关系到我国的粮食安全。借用生物学的承载力分析方法,设定耕地资源安全测度指标,建立了耕地资源安全测度模型,对郑州市1996—2005年10年来耕地资源安全进行了测算,并分析了耕地资源的时空特征。     

工业化与信息化互动对经济增长的影响——基于吉林省的实证分析

采用主成分分析方法测度工业化、信息化发展水平指数,运用线性滞后分布回归模型和多变量协整模型分析工业化与信息化的互动关系以及工业化、信息化对经济增长的影响.以吉林省为例,选取该省1984-2011年的相关数据整理分析后得出以下结论:吉林省工业化、信息化水平呈上升趋势,但工业化、信息化协调发展不够;工业化和信息化联系密切,工业化对信息化的促进作用大于信息化对工业化的促进作用.从长期看,工业化、信息化发展对经济发展有促进作用,且工业化对经济发展的促进作用远远大于信息化的作用.     

基于Moran’s I指数的京津冀地区PM2.5空间自相关分析

选取2014~2018年京津冀地区环境监测站点PM_2.5浓度观测数据,基于Moran's I指数,分析了该地区PM_2.5浓度的时空变化特征以及空间相关性。研究表明:2014~2018年京津冀地区PM_2.5浓度空间分布差异显著,2014年良、轻度、中度污染面积约占1/3,降至2018年以“良”为主;PM_2.5浓度空间分布北部、西部优于南部、东部地区,山区优于平原地区;PM_2.5浓度年平均值、IQR、Q1、Q3值及标准差均呈下降趋势,达到且接近于“良”以上程度的站点,从2014年2成增长至2018年8成;通过对历年及各月PM_2.5浓度全局Moran's I指数分析,I值(除7月外)均超过0.5,生成的P值均小于显著水平0.01,Z得分均超过了临界值2.58;年、月平均值均呈显著的集聚效应,年值集聚效应呈减弱趋势,月值集聚效应秋、冬季大于春、夏季,空间集聚效应与污染程度呈显著正相关;局部空间自相关历年、各月H-H集聚主要出现在京津冀南部地区,L-L集聚主要出现在北部地区。京津冀地区PM_2.5浓度值分布存在空间异质性,主要影响因素为地理、气候和经济环境。     

碳排放与经济增长关系及驱动因素分析——以西北地区为例

选取2000--2010年我国西北地区（陕西、甘肃、青海、宁夏、新疆）5个省区能源消费数据和经济数据作为样本数据,根据IPCC碳排放计算指南,测算出西北各地区的碳排放量;采用脱钩理论对西北地区碳排放与经济增长脱钩状态进行分析,运用LMDI分解方法构建碳排放因素分解模型深入研究其驱动因素.研究结论显示,2001-2010年西北地区经济增长与碳排放的脱钩状态趋于不稳定状态,其中2002年、2004年为强脱钩,2001年、2007年、2009年、2010年为弱脱钩,2003年、2005年、2008年为扩展性负脱钩,2006年为增长连接;经济规模持续扩大是西北地区碳排放快速增长的关键因素,能源强度下降是抑制西北地区碳排放增长的主要因素,产业结构优化升级和能源结构调整是控制碳排放增加的潜在因素.     

万盛大气污染特征分析及污染预报模型的建立

利用2017年4月1日~2019年3月31日万盛经开区万东北路站点的空气质量日均值监测数据进行分析发现,万盛大气污染具有很强的季节变化特征,冬半年主要污染物为PM 2.5,夏半年主要污染物为O 3,冬半年污染重于夏半年,颗粒物污染重于O 3污染。万盛污染以轻度污染为主,仅有冬季会出现中度以上污染天气,其首要污染物均为PM 2.5。利用多元回归模型和差分自回归移动平均模型(ARIMA)建立了万盛PM 2.5、PM 10与O 3的预报模型。通过对模型得出的预报值与实况值的比较来看,预报与实况的变化趋势基本一致,均可以较好的指示未来AQI的变化趋势。多元回归预报模型中,O 3的预报效果要远好于PM 2.5和PM 10;而ARIMA预报模型三者预报效果接近。总体来说,ARIMA(p,d,q)预报模型对颗粒物污染的预报效果要远好于多元回归预报模型,而O 3则两种模型预报效果接近。     

安宁河流域的光温水资源及生产潜力分析

从北至南依次连接冕宁县、西昌市、德昌县和米易县的安宁河流域,具有丰富的光温资源,平均气温14.1～19.4℃,≥10℃的积温4200～7300℃;年日照时数2044～2413h,年总辐射507～590KJ/cm~2;其中中下游区长夏无冬,热量资源为全省之冠。光温生产力达33903～56888kg/ha,增产潜力30228～52410kg/ha,增产潜力指数89.16%～92.13%。但因该流域干雨季节分明,干季降水不到10%,冬干春旱;雨季洪涝成灾,严重限制了光温生产潜力的发挥。自然生产潜力的光能利用率只占光合生产潜力的38%.实行水土综合改良,增加保灌面积和小春复种指数,以及立体开发,是挖掘生产潜力的有效措施。     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.     

AN APPLICATION RUNOFF MODEL STRATEGY FOR UNGAGED WATERSHEDS1

ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m²) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft³/sec (0.085 to 3.34 m³/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes.     

Using Paleo Reconstructions to Improve Streamflow Forecast Lead Time in the Western United States

In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.     

Urban ecological systems: scientific foundations and a decade of progress

Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.     

Predicting deer-vehicle collisions in an urban area

Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.     

MANGANESE CYCLE IN IMPOUNDMENT WATER

Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.     

Biodiversity and biotechnology

The maintenance of biodiversity is urged from many quarters and on grounds ranging from aesthetic considerations to its usefulness, particularly for biotechnology. But regardless of the grounds for preserving biodiversity, writers are generally in agreement that it should be preserved. But, in examining the various references biodiversity, such as species diversity, genetic diversity, and habitat diversity, it is apparent that we cannot aim to preserve biodiversityas such, since there are a number of conflicts in any such undertaking. In preserving one aspect of biodiversity, we damage another aspect. Five arguments which attempt to ground our moral concern for biodiversity are reviewed and critiqued, not only for their consistency but also for their power to move us to action. The final section of the paper shows how conflicts in the values of personal and environmental health can impair ethical action and especially policy formation.An earlier version of this paper was read at the conference on Agriculture, Food, and Human Values: Tradition and Change, Orlando, Florida, October 7–9, 1987.     

Sources and Transport of Phosphorus to Rivers in California and Adjacent States,U.S., as Determined by SPARROW Modeling

The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.     

Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands

Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.